If you've done any sort of command line stuff on a Unix-like OS, you've probably come across cat. It stands for 'concatenate', but most often we use it to simply spit out the contents of a file, like this:

$ cat myfile

So hang on - why is it called concatenate if we're only showing the contents of one file? Well, if you give cat one file, it just ...

If you do any amount of scripting with any Unix-like operating system, you are probably familiar with the hash-bang (also known as the shebang).

The hash-bang, put at the start of a script, instructs the OS to use the program following the #! to interpret the script. For example, if you've got a Perl script and you set the permissions to executable, you won't automatically be able to just ...